Make sure you answer each required part of each question you select. Show your work!

Thirty$-$three points for each Roman numeral question.

Freight car loadings over a $18$ year period at a busy port are as follows:

week

number

week

number

$1$

$220$

$10$

$380$

$2$

$245$

$11$

$420$

$3$

$280$

$12$

$450$

$4$

$275$

$13$

$460$

$300$

$14$

$455$

$6$

$310$

$15$

$500$

$7$

$315$

$16$

$465$

$8$

$360$

$17$

$501$

$9$

$400$

$18$

$541$

$$Determine the line trend equation for freight car loadings

$$Use your trend line equation to predict expect loadings for week $23$

$$Go back in time and use a three period moving average to forecast to forecast freight car loadings in weeks $17$ and $18.$ Then determine the forecast error of